1. Field of the Invention
A locking differential includes an annular center cam member freely rotatably supported within an annular central driver member without the use of any keying device, such as a snap ring, thereby to simply the construction and assembly of the differential, and to reduce cost. The center cam member and the central driver member have adjacent outer and inner circumferential surfaces, respectively, that are smooth, continuous, and uninterrupted. The holdout rings are rotatably connected at their remote ends with the clutch members by integral annular outer ribs that extend within corresponding grooves contained in the counterbore wall surfaces.
2. Description of Related Art
Locking differentials are well known in the patented prior art, as evidenced by the patents to Knoblock U.S. Pat. No. 2,329,059, Bawks (the present inventor) U.S. Pat. No. 4,424,725, and Edwards et al U.S. Pat. No. 4,745,818. In these prior art patents, the annular center cam member is normally arranged concentrically within, and keyed to (by a snap ring or the like), the annular central driver member, thereby to prevent relative axial displacement between the two components. When one output shaft overruns the other by a predetermined amount, the overrunning clutch member slidably mounted on the side gear associated with the overrunning shaft is cammed out by the teeth on the central driver member and on the clutch members, thereby to disengage the overrunning output shaft as long as the overrunning condition exists.
These known differentials require a relatively large number of complicated parts, and are difficult and expensive to manufacture and assemble. For example, in the Bawks and Knoblock patents, the spring biasing means for the locking differentials are arranged concentrically within the clutch members and the center cam member, thereby complicating the assembly and servicing of the differential. In the clutch members of the Edwards patent, the camming teeth are arranged in a circular pattern adjacent the inner circumference of the opposed faces of the clutch members, and the driving teeth are arranged in an outwardly spaced circular pattern adjacent the outer circumferences of the clutch members, with the holdout rings being mounted at their remote ends in grooves contained in the clutch member faces between the cam teeth and the driving teeth.
Some of the known differentials present the problem that the holdout ring can jump over the spider key during a speed variation between the spider and clutch, thereby causing the clutch to be non-parallel with the spider. This will result in damage to the clutch teeth and failure of the differential.
The present invention was developed to provide an improved less costly locking differential that requires fewer parts, is easier to manufacture and assemble, and is more durable in operation, and easier to service.